1. Field of the Invention
The present invention relates to power generation systems for marine vessels, and more specifically, to an integrated open cycle propulsion system for an underwater vessel.
2. Prior Art
Vehicles that operate underwater are useful for performing tasks below the sea surface in such fields as deep-water salvage operations, navy and marine operations, underwater telecommunications, offshore petroleum and mining, and oceanographic research. Many of these applications are completed by small-scale underwater vehicles that can be either manned or unmanned (remotely operated). These unmanned vehicles are commonly known as Unmanned Underwater Vehicles (UUVs).
Generally, these small-scale underwater vessels have used a variety of conventional propulsion systems. Some of the traditional power/propulsion generation systems are closed loop, such as U.S. Pat. No. 6,610,193, requiring complex components to capture the exhaust stream and to generate power. These components (turbines, condensers, generators, etc.) can be quite large and massive, taking up significant space and slowing down the underwater vessel because of their weight. In these conventional propulsion systems, the power generated is used to power motors that are used to power the external propellers and generate thrust. The high-pressure stream into the turbine can be generated using a combustion reaction.
Some traditional propulsion generation systems use complex fuels, such as methane or other hydrocarbons, or oxidizers, such as hydrogen peroxide, to generate the exhaust stream, such as in U.S. Patent Publication No. 2003/0153216, and may have environmentally unfriendly exhaust products ejected into the ocean. These compounds require specific safety practices and may not be easy to replace while in the field (out at sea).
Other conventional propulsion generation systems use pump jets that ingest seawater and then use electrically powered pumps to push water out of the vehicle to generate thrust, such as in U.S. Pat. No. 4,341,173. In these propulsion generation systems, the electrical system used to power the pumps (batteries) would have to be recharged and/or replaced.
Large underwater vessels typically do not require a high speed mode. High speed is usually only required for underwater weapon systems, such as torpedoes, which are not re-used and are expendable underwater vessels. Torpedoes use electrical and combustion based systems to generate power/thrust. The propulsion systems have included thrust based systems that eject high pressure water, or propeller based systems.
However, none of the prior art provides for a propulsion system that can provide a high speed for a marine vessel without adding significant weight to the vessel, and without using any complex fuels that may cause safety concerns. Accordingly, there is a need for a propulsion generation system for a marine vessel that provides for a high speed mode for large submersible vessels, without the drawbacks found in the prior art.